export default {
	_keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
	encode(str) { // 加密
		var output = "";
		var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
		var i = 0;
		str = this._utf16to8(str);
		while (i < str.length) {
			chr1 = str.charCodeAt(i++);
			chr2 = str.charCodeAt(i++);
			chr3 = str.charCodeAt(i++);
			enc1 = chr1 >> 2;
			enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
			enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
			enc4 = chr3 & 63;
			if (isNaN(chr2)) {
				enc3 = enc4 = 64;
			} else if (isNaN(chr3)) {
				enc4 = 64;
			}
			output = output + this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) + this._keyStr.charAt(enc3) + this
				._keyStr.charAt(enc4);
		}
		return output;
	},
	decode(input) { // 解密
		var output = "";
		var chr1, chr2, chr3;
		var enc1, enc2, enc3, enc4;
		var i = 0;
		input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
		while (i < input.length) {
			enc1 = this._keyStr.indexOf(input.charAt(i++));
			enc2 = this._keyStr.indexOf(input.charAt(i++));
			enc3 = this._keyStr.indexOf(input.charAt(i++));
			enc4 = this._keyStr.indexOf(input.charAt(i++));
			chr1 = (enc1 << 2) | (enc2 >> 4);
			chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
			chr3 = ((enc3 & 3) << 6) | enc4;
			output = output + String.fromCharCode(chr1);
			if (enc3 != 64) {
				output = output + String.fromCharCode(chr2);
			}
			if (enc4 != 64) {
				output = output + String.fromCharCode(chr3);
			}
		}
		return this._utf8to16(output);
	},
	_utf16to8: function(str) {
		var out, i, len, c;
		out = "";
		len = str.length;
		for (i = 0; i < len; i++) {
			c = str.charCodeAt(i);
			if ((c >= 0x0001) && (c <= 0x007F)) {
				out += str.charAt(i);
			} else if (c > 0x07FF) {
				out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
				out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
				out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
			} else {
				out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
				out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
			}
		}
		return out;
	},
	_utf8to16(str) {
		var out, i, len, c;
		var char2, char3;
		out = "";
		len = str.length;
		i = 0;
		while (i < len) {
			c = str.charCodeAt(i++);
			switch (c >> 4) {
				case 0:
				case 1:
				case 2:
				case 3:
				case 4:
				case 5:
				case 6:
					case7:
						out += str.charAt(i - 1);
					break;
				case 12:
				case 13:
					char2 = str.charCodeAt(i++);
					out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
					break;
				case 14:
					char2 = str.charCodeAt(i++);
					char3 = str.charCodeAt(i++);
					out += String.fromCharCode(((c & 0x0F) << 12) |
						((char2 & 0x3F) << 6) |
						((char3 & 0x3F) << 0));
					break;
			}
		}
		return out;
	}
};
